1. Field of the Invention
The present invention relates to a thin film capacitor and a method of manufacturing the same.
2. Related Background Art
Recently, a reduction in profile of electronic components has been accomplished rapidly, resulting in the requirement for a multilayer thin film capacitor that is composed of a lower electrode, alternately disposed dielectric thin films and electrode films, and an upper electrode, in that order. Thin film capacitors having such multilayer dielectric thin films are disclosed in, for example, National Publication of International Patent Application No. 2006-511088 (Patent Literature 1) and Japanese Unexamined Patent Application Publication No. 8-78283 (Patent Literature 2).
In the thin film capacitor described in Patent Literature 1, particularly in FIG. 7D, electrode layers and dielectric layers are alternately deposited on a dielectric base layer into a stepped profile. The dielectric layers have edges flush with those of the alternately-deposited electrode layers in the stacking direction.
The thin film capacitor described in Patent Literature 2, as shown in FIG. 2, is formed by alternately depositing dielectric thin films and metals on a metal foil, each of the metals being deposited through a mask, and processing the resulting stack by ion milling from the topmost layer which is the farthest from the metal foil, for tapering.
Unfortunately, in the thin film capacitor described in Patent Literature 1, because the edges of the dielectric layers are designed to be flush with the edges of the electrode layers in the stacking direction, the edges of the dielectric layers sometimes project like shelves from the electrode layers for the reason of manufacturing tolerances and variations. As a result, the edges of the dielectric layers were broken into debris, which cause a problem particularly in case of forming the thin film capacitor by wet etching.
To cope with the problem, the electrode layer just below one dielectric layer may have an edge protruding from the dielectric layer, however an unnecessary protrusion of the edge could cause a short circuit due to the contact between the protruding electrodes.
The thin film capacitor described in Patent Literature 2 has a structure having tapered side surfaces where electrodes are deposited for electrical connection between the internal electrodes, and thereby adjacent electrodes are easily brought into contact with each other to be a short circuit depending on the accuracy of the patterning of the internal electrodes and the taper etching.